America's toxic mining pools: Ticking time bombs?

There are over 500,000 abandoned mines in the U.S. containing noxious brews.

On August 5, 3 million gallons of toxic sludge gushed out of the long-abandoned Gold King mine near Silverton, Colorado, and into the Animas River. The Tang-colored torrent, percolating with arsenic, lead and other pollutants, was inadvertently unleashed by Environmental Protection Agency (EPA) contractors attempting to clean up wastewater that's been accumulating since the mine closed in 1923.

Brennan Linsley | AP

Water flows through a series of sediment retention ponds built to reduce heavy metal and chemical contaminants from the Gold King Mine wastewater accident outside Silverton, Colorado, August 14, 2015.

The poisonous plume ran downstream into waterways in Utah, New Mexico and the Navajo Nation, but subsequent tests reportedly show that the toxins have dissipated and the water is safe. Regardless, the episode has revealed an even more frightening, long-festering problem: There are an estimated 500,000 abandoned mines nationwide, though mostly in Western states, an unknown number of which contain similarly noxious brews that could potentially be released and contaminate innumerable water systems and adjoining lands.

The Denver Post's Bruce Finley reported that "230 other old mines [in Colorado are] leaking heavy metals-laced muck into headwaters of the nation's rivers. These old mines have leaked so much for so long, thousands of gallons a minute, that state agencies don't track the combined toxic flow." The EPA has calculated that 40 percent of river headwaters in the West are contaminated by acid mine drainage, which occurs when sulfides in mines are exposed to air and water, creating what's basically sulfuric acid.

"These are disasters we know are waiting to happen," said Jennifer Krill, executive director of Earthworks, a Washington-based environmental group that's been advocating for reform of a 143-year-old federal law seen as a major source of the dilemma. The General Mining Law of 1872, signed by President Ulysses S. Grant during the unbridled building of the West, permitted mining of gold, silver and other hard-rock minerals on public lands for next-to-nothing lease prices, zero royalties (unlike those paid by oil, gas and coal lessees), scant environmental oversight

Despite numerous attempts, the law remains on the books, but that may soon change. "An entire river system turning bright orange ought to be the wake-up call for Americans that it's time to stand up and take notice," Krill stated.

"If we modernize the 1872 law, we'll start to reverse what's going on by making sure the mining industry takes responsibility for its messes."-Jennifer Krill, executive director, Earthworks

Perhaps, but while the horrible images remain fresh, Rep. Raúl Grijalva, an Arizona Democrat, has already called for a congressional hearing on his recently proposed legislation to modernize the antiquated law. Essentially, HR 963—the Hardrock Mining Reform and Reclamation Act of 2015—would levy an 8 percent royalty on new and existing hard-rock mines to create a federal fund to supplement the meager public and private money currently spent on cleanup and remediation activities. Democratic Sen. Martin Heinrich of New Mexico announced that he will introduce a similar bill in the Senate next month.

"The federal estimate for cleaning up contaminated mines is $54 billion, which I think is low-balling," Grijalva said. "While this [Gold King] incident was a mistake by EPA, the underlying problem is the huge number of abandoned hard-rock mines that are effectively ticking time bombs threatening our rivers and our lands. Congress must provide robust funding to clean up these mines, which is exactly what my [bill] does."

Read MoreEPA downplays dangers of mine spill, but concerns linger

"No one is arguing that there isn't clearly a problem," said Luke Popovich, vice president of external communications for the Washington, D.C.-based National Mining Association. Yet changing the 1872 law is not the solution, he said, adding that "it is just a predictable way to exploit this accident by raising a completely irrelevant issue." He cited several post-Earth Day laws—including the Clean Water Act and Clean Air Act—that have addressed environmental concerns over mining. "We're probably the most heavily regulated industry in the U.S.," he said.

Instead, the mining industry favors so-called Good Samaritan legislation, which would allow for private groups and mining companies to clean up toxic sites, but at no liability in case of spills like those into the Animas River. "We've discussed royalties on new mines," Popovich said, "if they're reasonable." He declined to suggest a figure.

Earthworks, meanwhile, will continue its push for reform of the mining law. "The government shouldn't be paying for the cleanup," Krill said, noting the EPA's related shoestring budget. "If we modernize the 1872 law, we'll start to reverse what's going on by making sure the mining industry takes responsibility for its messes."